I must have cleaned the sensors on my 10D and 20D a hundred times now without any problems. The first time you swipe a sensor is a bit nerve wrecking but once you get the hang of it it's a simple process. I use Pec-Pads and Eclipse fluid. A very cheap solution to an ugly problem ($0.20 per sensor swipe)

We use our patented Dry Dry Wet Method. Wet is the last scenario.It's quite safe with brushes in the "Sensor Brush" method. If the dust is oily or particularly stuck then it's a wet clean.

I got quote $80 here in Australia. Rediculous for a five minute job (even when shooting test shots at F16 against a white wall)

Method

Shoot a test shot at F16 against a white wall (RAW Preferred)

If you "Auto Level in PS" or something similar it'll adjust the contrast etc so the dust is obvious. Many are surprised by the dust they didn't think they had.

I use sensor brushes and I blow a puffer through one vigorously and then wipe the sensor in a pattern (which I make up each time). I did have cans of re-air, but I needed a method I could use in the field.

I then recheck with another photo and repeat until done.

If the dust is stubborn and sticky, I am out with the PEC pads and fluid.

On my 1Ds3 and 1D3 I've never done wet.on the Old 1D2s.... maybe once on one of them...5D once5D2 never20D . . once